1. Field of the Invention
This invention relates to three-wheel motorcycles and more particularly to provision of special swing-arm, independent suspension, rear frame assembly for a storage box for use in police and emergency type vehicles.
2. Description of the Prior Art
Three-wheel emergency vehicles or motorcycles are generally of two types: those having a side car for a passenger; and the type involved here, those having a rear storage box disposed between driven rear wheels. In the old Harley Davidson type of police vehicles, the engine drove a chain to a separate gear box, and in turn the rear axle was driven by a chain and gear assembly. The Harley used a one-piece frame which included both the front frame and the rear frame containing a rigid rear axle. It did not involve a swing-arm suspension of any type. The box was sprung from the rear solid, one-piece frame. More recently, the "Trident" brand three-wheel police vehicle manufactured by KVV Enterprises, Inc. of Cincinnati, Oh., employs a "box type" suspension having a one-piece frame in which a symmetric rear axle is mounted on a swivel plate, one end of which is sprung to the frame. The box is also mounted on springs to the rear frame.
In the case of the Harley Davidson, mounting the box on springs but having no springs in the frame causes frame fatigue, and an excessively loose box-type mounting. In addition, the box is more difficult to dismount as it is mounted on the springs. Similarly, mounting the rear axle on springs as in the case of the "Trident" provides a somewhat smoother ride as compared to the Harley, but is more complex to service, particularly the offset drive shaft to the symmetric differential.
Accordingly, there is a need for provision of an improved rear suspension and box assembly for three-wheel type of emergency and police vehicles.